Further to my earlier poem about English plurals, here is one about verb tenses:

We'll open with the simple present tense,Which basically follows common sense;It's used for current states (I am, I know)And customary actions like I go,Declaratory statements (I resign!)And sequenced items (First I draw this line...)It stands for future time in When I dieAnd If they go to Russia next July.Some tales are told entirely in the present(Their brisk, no-nonsense tone I find unpleasant),While stand-up comics use this same deviceTo give their threadbare monologues more spice.

The simple tense has its progressive sibling,Displayed in phrases such as I am nibbling,And used where present action is ongoingLike You are shivering or It is snowing.Some foreign students tend to use this formIn ways that flout the native English norm –'I am not knowing what you mean', they cry;'That's wrong', we say, though we may not know why.

The past tense is not normally a mystery;It covers things that now belong to history(Rome conquered Gaul) or feature in a story(The dragon's death was sickeningly gory).It's used in the subjunctive mood to showWhat could be factual, but is not so:If I were king, If children had the vote(The 'was' form's solecistic here, please note).Sometimes the past is harder to explain –Why do we say 'It's time we had some rain'?

'They were attacking' is the past progressive;Further remarks thereon would be excessive.

The future tense is formed with shall or will;The use of these two verbs requires some skill.In practice, though, the 'will' form is enough,So you can skip the complicated stuff.The 'going to' alternative is good;The past auxiliary verb is 'would'.The latter form can show a suppositionDependent on some specified condition(If she attacked a bull, she would be killed),Which, in 'I knew she would be', is fulfilled.

The perfect tense (The storm has now abated)Applies where past and present are related.'I've had a message that my aunt has died'May indicate that I've not yet replied(Whereas 'I heard about her death' would showIt should have been acknowledged long ago).

We have a range of other compound tenses –Past perfect(They had not repaired the fences)And future perfect(I'll have reached the station),Together with the 'would have' variation.Each one has a progressive version too;The task of listing these I'll leave to you.

These verb forms, learned by nurture or by course,Comprise a rich and flexible resourceFor good expression, from ecstatic blissTo plain didactic doggerel like this.